Whilst City do not possess Inter's history, which includes 18 Scudettos and three European Cups, they have spent a long time in the shadow of a major city rival.
Inter won a single Serie A title and three UEFA Cups between 1982 and 2005, a period in which AC Milan won the Italian championship seven times and celebrated four of their seven Champions League triumphs.
So, as the man who ended that period of torment for Inter, Mancini knows a little of what City have suffered at Manchester United's hands for the past four decades.
"Before I arrived at Inter, they didn't win for 19 years," he said.
"For Inter this was very difficult because Milan won a lot of trophies.
"It is the same situation here.
"It is clear Manchester City doesn't have Inter's history but they have also started to build a new team, a strong team and has got to the same level as the other one."
Mancini's men have already inflicted some pretty hefty damage in the two years he has been around.
Last season's FA Cup semi-final win was seismic in that it paved the way for the club's first silverware in 35 years.
And then in October came that staggering 6-1 triumph at Old Trafford that sent shockwaves around the world and leaves City on the brink of a hat-trick of derby victories for the first time since 1969 when the blue and red halves of the city collide in the FA Cup third round on Sunday.
Yet, although his club's supporters may bridle at the suggestion, Mancini still concedes his team are inferior.
"Manchester United are the best team in England," he said.
"Maybe not now because they have six or seven important players injured.
"But they have a strong team with a strong mentality and they are at the top."
As Mancini said very similar things about Chelsea last term, only for United to win the league, either his comments should be taken with a pinch of salt or he is a lousy judge of opponents.
"We can't be like them in two years," he said.
"They have had this mentality for 25 years.
"We can improve if we continue to win, if we win the championship or other cups. We started it last season. But in two years it is impossible."